Adding declarative information to the essential procedural information in instructions for use might have different effects. Previous research examined the effect of declarative information on the ability to work with the system that is described in the instructions. However, the results of the various experiments were not conclusive. Moreover, other possible effects of declarative information were never investigated before. In the present experiment, the effects of two different types of declarative information on task performance, on cognitive load and on self-efficacy were examined. The results demonstrated that the two types of declarative information negatively affected cognitive load and self-efficacy ratings. The effects on task performance were positive, but moderate.